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X-RAY RUNS: Apply for Beamtime

2017  Nov 1 - Dec 21

2018  Feb 7 - Apr 3
2018  Proposal/BTR deadline: 12/1/17

2018  Apr 11 - Jun 4
2018  Proposal/BTR deadline: 2/1/18

 


Abstracts

Tuesday, June 9th

 

 
"Understanding Organic Semiconductor Polymorphism using High Speed in-situ Optical and X-ray Diffraction Methods"

Gaurav Giri, Ruipeng Li, Detlef Smilgies, Aram Amassian, Zhenan Bao

Abstract: Organic electronics have been considered a leading candidate to make transparent and flexible electronics at a low cost. We have previously shown that the solution shearing method is a process that improves electrical performance for a range of OSCs, and the method is compatible with roll to roll industrial processing. This method can also tune the polymorph formation in OSCs, enabling high performance transistors without changing the OSC chemical structure. However, it is difficult to study the morphological and polymorph formations that enable high OTFT performance in situ. Not only does the thin film crystallize at a fast time scale, the evaporation front, where the crystal grows from the solution, is very small. The entire evaporation front can be less than 200 microns. Thus, the solution evolves into a crystallized thin film within seconds, and within an area less than 0.2 mm wide.

We use an X-ray ‘microbeam’ at the Cornell High Energy Synchrotron Source, with a beam width of < 20 microns, in conjunction with a high speed detector to resolve and follow crystallization from solution of the OSC during solution shearing. We have collected up to 100 frames per second X-ray images, and are able to create grazing incidence x-ray diffraction movies to easily see how crystallization occurs in the solution shearing system in real time. We also use an optical microscope trained at the evaporation front, which we can use to collect optical videos of the evaporation front at up to 10,000 frames per second. Being able to simultaneously study kinetic crystallization using both optical and X-ray movies helps us understand how different processing conditions result in various polymorphs. We study the model OSC 6,13-bis(triisopropyl)-silylethynyl pentacene (TIPS-pentacene) and show that confinement of the growing thin film plays a key role in forming metastable polymorphs, and that the film formation proceeds downwards from the air-solution interface. We generate metastable crystal polymorphs through other solution processing conditions as well. This is the first time such a fast rate of data collection has been utilized for grazing incidence X-ray diffraction.

 

 
"Manipulating and Patterning Protein Crystals using
Surface Acoustic Waves"

Jarrod B. French
Departments of Chemistry and Biochemistry & Cell Biology, Stony Brook University

Abstract: Advances in modern X-ray sources and detector technology have made it possible for crystallographers to collect usable data on crystals of only a few micrometers or less in size. Despite these developments, sample handling techniques have significantly lagged behind and often prevent the full realization of current beamline capabilities. In order to address this shortcoming we have developed a surface acoustic wave-based method for manipulating and patterning crystals. This method, which does not damage the fragile protein crystals, can precisely manipulate and pattern micrometer and sub-micrometer sized crystals for data collection and screening. The technique is robust, inexpensive, and easy to implement. This method not only promises to significantly increase efficiency and throughput of both conventional and serial crystallography experiments, but also will make it possible to collect data on samples that were previously intractable.

 

 
"Studying the Micromechanics of Martensitic Phase Transformations using High Energy Diffraction Microscopy"

Aaron Stebner
Colorado School of Mines

Abstract: Martensitic phase transformations enable advanced properties and performances of many structural and functional materials. They impart remarkable toughness and strength to steels, shape-morphing capabilities to shape memory alloys, and thermal energy harvesting abilities to multiferroics. Modern theories of their micromechanics are nearly 80 years mature. Experiments to verify these theories at the micro-scale, however, are a relatively new success, as these transformations are often partially, if not fully reversible, thus ex-situ observations of micro-scale mechanisms are difficult. Recently, non-destructive in-situ diffraction experiments, especially far-field High-Energy Diffraction Microscopy (HEDM) techniques, have enabled empirical micromechanical observations at the same scales the theories have spanned for many decades. Some of the pioneering work in this regard has been performed on the A2 and F2 beam lines at CHESS. Nickel-titanium and iron-palladium shape memory alloys have been used as model materials. In this presentation, we will review these data, discussing the successes and remaining challenges in their analysis and application to verify, validate, and challenge existing theories.

 

 
"Nanomaterials under Stress: A New Opportunity for Nanomaterials Synthesis and Engineering"

Hongyou Fan
Sandia National Laboratories and University of New Mexico, Albuquerque, New Mexico

Abstract: Precise control of structural parameters through nanoscale engineering to improve optical and electronic properties of functional nanomaterials continuously remains an outstanding challenge. Previous work has been conducted largely at ambient pressure and relies on specific chemical or physical interactions such as van der Waals interactions, dipole-dipole interactions, chemical reactions, ligand-receptor interactions, etc. In this presentation, I will introduce a new Stress-Induced Fabrication method that uses mechanical compressive force applied to nanoparticles to induce structural phase transition and to consolidate new nanomaterials with precisely controlled structures and tunable properties. By manipulating nanoparticle coupling through external pressure, instead of through chemistry, a reversible change in their assemblies and properties can be achieved and demonstrated. In addition, over a certain threshold, the external pressure will force these nanoparticles into contact, thereby allowing the formation and consolidation of one- to three-dimensional nanostructures. Through stress induced nanoparticle assembly, materials engineering and synthesis become remarkably flexible without relying on traditional crystallization process where atoms/ions are locked in a specific crystal structure. Therefore, morphology or architecture can be readily tuned to produce desirable properties for practical applications.

 

 
"Assessing Intrinsically Disordered Protein Structure and Function"

Scott A. Showalter
Department of Chemistry, The Pennsylvania State University, University Park, PA

Abstract: Intrinsically Disordered Proteins (IDPs) partially or completely lack a co-operatively folded structure under native conditions, preventing their equilibrium state from being adequately described by a single structural model. Our view is that IDPs do possess native structure that is responsible for imparting their specific functions; describing these structures simply requires a broadening of the traditionally narrow structure-function paradigm, beyond the current models developed for cooperatively folding systems. We have shown that 13C direct-detection NMR methods are well suited to generating quantitative and comprehensive structural constraints for IDP ensembles. When combined with small angle x-ray scattering (SAXS) data, these constraints are sufficient to generate low resolution models for the native states of non-folding proteins. The structural ensembles we have generated will be discussed in the context of their impact on protein-protein interactions. Emphasis will be placed on the capacity of IDPs to substantially alter their conformational sampling in response to post-translational modification, which has arisen as a prevalent mechanism for regulating molecular recognition when IDPs interact with other proteins.

 

 
"Raising the superconducting Tc by adding defects in
1/8 doped La2-xBaxCuO4"

Maxime Leroux
Argonne National Laboratory

Abstract: The question of how charge order coexists or competes with superconductivity is a subject of intense and active research, as its resolution could be key in explaining the origin of superconductivity in cuprates superconductors. Here we report that the Tc of La1.875Ba0.125CuO4 (LBCO) increases by up to 50%, from 4 to 6K, after proton irradiation. At high enough energy, proton irradiation creates a uniform density of small nm-sized amorphous clusters and point defects, which results in a uniform and isotropic 3D distribution of defects [1]. However, it is well known that non-magnetic defects are pair-breaking for d-wave superconductivity, and should therefore reduce Tc• Using x-ray scattering to follow the temperature dependence of the charge order peak, we speculate that proton-induced disorder directly affects the balance between competing density wave and superconducting ground states.

[1] Jia, Y. et al. Appl. Phys. Lett. 103, 122601 (2013); M. A. Kirk, Cryogenics 33, 235 (1993), M. A. Kirk, Y. Yan, Micron 30, 507 (1999).

This work is supported by the Center for Emergent Superconductivity, an Energy Frontier Research Center funded by the U.S. D.O.E., Office of Science, Office of Basic Energy Sciences and by the D.O.E, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

 

Wednesday, June 10th: WORKSHOP I, XES Workshop

 

 
"X-ray Emission Spectroscopy as a Probe of Catalysis"

Serena DeBeer
Max Planck Institute for Chemical Energy Conversion and the Department of Chemistry and Chemical Biology, Cornell University

Abstract: A basic introduction to both non-resonant and resonant X-ray emission spectroscopies (XES) will be given. X-ray emission measurements involve the ionization of core electrons, followed by the relaxation of electrons from filled levels to repopulate the core hole, which results in emitted fluorescent photons. Due to large separations in core ionization energies, XES is an element specific technique. In the case of a 1s core ionization, the resultant XES spectrum can be divided into three regions: the K-alpha region, the K-Beta region and the valence-to-core region, resulting from 2p-1s, 3p-1s and valence-1s transitions, respectively. The K-Beta region is of particular interest for transition metals as the strong 3p-3d exchange interaction renders the spectra spin state dependent. The valence-to-core region, on the other hand, provides a probe of ligand identity, protonation state and ionization potential. Hence XES methods provide a strong complement to more traditional X-ray absorption measurements. The information content of these spectra can be further enhanced through resonant measurements. The element specificity of these methods and the ability to study samples in almost any form, renders these methods very useful for studying countless questions in inorganic catalysis. Recent applications in biological and chemical catalysis will be highlighted. Future opportunities utilizing dispersive methods to follow dynamic processes will also be discussed.

 

 
"Biological Applications of X-ray Emission Spectroscopy: Structure and Mechanism of Ribonucleotide Reductases"

Christopher J. Pollock, Hannah R. Rose, Ailiena K. Maggiolo, Beth J. Blaesi, Maria E. Pandelia, Amie K. Boal, Carsten Krebs, J. Martin Bollinger
The Pennsylvania State University

Abstract: Kβ x-ray emission spectroscopy (XES) is a rapidly developing spectroscopic tool for the study of inorganic and bioinorganic systems. These spectra can be broken down into two distinct regions—the Kβ mainline consisting of metal 3p to metal 1s transitions and the valence-to-core (VtC) region comprised of transitions from valence, ligand-localized orbitals to the metal 1s. Both have been shown to contain valuable chemical information: The Kβ mainline is sensitive to the metal spin state as well as the metal-ligand covalency while the VtC region contains information about ligand identity and electronic structure. Furthermore, as a core spectroscopy, XES is element specific, allowing selective access to this information even if the metal of interest constitutes only a small percentage of the sample. These attributes make XES particularly attractive for the study of bioinorganic systems, where the understanding of function often requires detailed chemical knowledge of the metal sites in these proteins. Herein, applications of Kβ XES to the study of ribonucleotide reductases (RNRs) will be highlighted, in particular how XES allows access to information concerning the structure and mechanism of the inorganic cofactors of these enzymes. The potential for examining two metals simultaneously via “two-color” XES is explored with a case study of the MnFe heterobimetallic active site of RNR from the pathogen Chlamydia trachomatis.

 

 
"Local moment physics in iron based superconductors"

Young-June Kim
University of Toronto

Abstract: Understanding magnetism is at the heart of iron-based superconductivity research. Since there are multiple orbitals involved in the electronic structure of iron pnictides and chalcogenides, both local and itinerant descriptions seem to be necessary. I will give an overview of our recent x-ray emission spectroscopy (XES) studies, which support this viewpoint. The Fe Kbeta XES is a fast, local probe that is bulk-sensitive and couples directly to the d-electron moment. This is particularly useful for studying paramagnetic phases of iron superconductors. We found that local magnetic moments are doping- and temperature-independent in a wide range of Fe based superconductors. However, they are extremely sensitive to the structural details. In order to explain the observed experimental results, both density functional theory and local spin model description will be discussed.

 

 
"Elucidating Biological Energy Transduction from Ammonia"

Kyle M. Lancaster, Jonathan D. Caranto, Meghan A. Smith, Avery Vilbert, and Richard C. Walroth
Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca NY 14853 (email: kml236@cornell.edu)

Abstract: Nitrification, the oxidation of ammonia to nitrite and nitrate, is a key entry point for fixed nitrogen to return to the atmosphere as dinitrogen.1 Nitrification is the root of tremendous economic loss in agriculture as well as a major ecological hazard via nitrogenous eutrophication.2,3 Molecular details concerning the elementary, multi-electron chemical steps whereby ammonia is oxidized to hydroxylamine and ultimately to nitrite remain elusive. This may be attributable in part to the difficulty associated with accessing sufficient quantities of relevant enzymes for biophysical characterization. Nevertheless, such insights are attractive because they hold the promise of inspiring novel, green chemical methods for difficult bond activations and multi-electron transformations. This talk will describe our successful construction of a recombinant expression system for a functional nitrification metabolism in M. smegmatis. This system opens the door for genetic as well as chemical and spectroscopic studies of the enzymes ammonia monooxygenase and cytochrome P460. Preliminary X-ray, EPR, and NMR spectroscopic data as well as electronic structure calculations germane to reactive intermediates in both proteins will be presented.

Nitrification

 
[1] Hooper, A. B.; Vannelli, T.; Bergmann, D. J.; Arciero, D. M., A. Van Leeuw. J. Microb. 1997, 71, 59-67.
[2] Gruber, N.; Galloway, J. N., Nature 2008, 451, 293–296.
[3] Canfield, D. E.; Glazer, A. N.; Falkowski, P. G., Science 2010, 330, 192–196.

 

 
"X-ray Emission Spectrometers: Now and Coming Soon"

Kenneth D. Finkelstein
CHESS, Cornell University

Abstract: This talk covers three areas: optical principles and instruments used to collect x-ray emission by scanning one energy at a time, how this is done at CHESS, and our approach for developing energy dispersive spectrometers for simultaneous collection of the full spectrum.

We describe the Rowland Circle (RC), its application for XES, and strengths and limitations. With a few parameters one can estimate signal rates and energy resolution, useful for designing experiments. CHESS recently deployed a versatile new RC instrument called DAVES. We outline how spectroscopy is done by scanning DAVES and collecting images.

RC spectrometers, with multi-crystal analyzer arrays, collect over large solid angle but they are not very useful if the sample is changing in time. In this case, one solution is the von Hamos dispersive spectrometer, utilizing a flat crystal analyzer and linear or area detector. The full spectrum emitted from a point source is dispersed linearly in position on the detector plane. Signal rate for these systems are limited by bandwidth accepted by the analyzer reflection. We describe dispersive spectrometers, based on micro-fabricated bendable analyzers that maximize collection solid angle & efficiency.

 

 
"Holistic Approach to Probe the Electronic Structure of Transition Metal Complexes from X-ray Spectroscopy"

Mario U. Delgado-Jaime and Frank de Groot
Utrecht University

Abstract: Charge transfer multiplet simulations are a great tool for exploring the effects of atomic interactions, ligand field and charge transfer parameters in core-level x-ray spectroscopies [1,2]. Moreover, they are useful to extract valuable information related to bonding, spin state and crystal field when compared to experiment [1,3,4]. In doing so, many have anticipated the possibility of multiple solutions (in the form of multiple combination of parameters), but the extent to which this is true has remained elusive.

We propose a new methodology implemented in Blueprint XAS [5,6] to evaluate the uncertainty of parameters used for multiplet simulations. The creation of the model involves the inclusion of all the spectral components at once. For example, in XAS this would include, in addition to the simulation parameter(s), the edge jump(s) and the background. Thus, the effect of variations in the background and the parameters modeling the edge resulting in different sets of multiplet simulation parameters gets also explored. Blueprint XAS is a Matlab-based toolbox that reduces the bias on choosing the start points in fitting problems and from which several possible good fits are found [5,6]. This allows the estimation of uncertainties for each parameter and the evaluation of the uncertainty in other properties that depend on these solutions (e.g., sum rules, relative compositions, normalized intensities, etc.)

Back in 2003 [7], a projection method based on Multiplet Simulations was proposed to extract covalency from the L-edge XAS spectra of transition metal complexes. A comparison to the DFT calculations of well-established iron complexes suggested a reasonable agreement to the values obtained by this method. We recently found, however, that the agreement is much better than originally realized. We apply the Holistic approach to validate the structure obtained from DFT calculations; by first fitting the Multiplet Simulations to the experimental data and subsequently apply the projection method to extract the covalency. Several examples will be presented and discussed.

[1] F.M.F de Groot, “Multiple Effects in X-Ray Spectroscopy”, Coord. Chem. Rev., 2005, 249, 31-63.
[2] E. Stavitski, F. M.F. de Groot, “The CTM4XAS program for EELS and XAS spectral shape analysis of transition metal L edges”, Micron, 2010, 41, 687–694.
[3] R. K. Hocking, E. C. Wasinger, F. M. F. de Groot, K. O. Hodgson, B. Hedman, and E. I. Solomon, “Fe L-Edge XAS Studies of K4[Fe(CN)6] and K3[Fe(CN)6]: A Direct Probe of Back-Bonding”, J. Am. Chem. Soc., 2006, 128, 10442-10451.
[4] R. K. Hocking, E. C. Wasinger, Y.L. Yan, F. M. F. deGroot, F. A. Walker, K. O. Hodgson, B. Hedman, and E. I. Solomon , “Fe L-Edge X-ray Absorption Spectroscopy of Low-Spin Heme Relative to Non-heme Fe Complexes: Delocalization of Fe d-Electrons into the Porphyrin Ligand”, J. Am. Chem. Soc., 2007, 129, 113-125.
[5] M.U. Delgado-Jaime and P. Kennepohl, “Development and exploration of a new methodology for the fitting and analysis of XAS data”, J. Sync. Rad., 2010, 17, 119-128.
[6] M.U. Delgado-Jaime, C. P. Mewis, and P. Kennepohl , “Blueprint XAS: A Matlab-based toolbox for the fitting and analysis of XAS spectra”, J. Sync. Rad., 2010, 17, 132-137.
[7] Erik C. Wasinger, Frank M. F. de Groot, Britt Hedman, Keith O. Hodgson and Edward I. Solomon, “L-edge X-ray Absorption Spectroscopy of Non-Heme Iron Sites: Experimental Determination of Differential Orbital Covalency”, J. Am. Chem. Soc., 2003, 125, 12894-12906.

 

Wednesday, June 10th: WORKSHOP II, MacCHESS Workshop

 

 
"Introduction to fast-framing detectors"

Dr. Kate Shanks
Cornell Detector Group, Cornell University

Abstract: Detectors capable of operating at high frame rates while maintaining good noise performance expand opportunities for performing time-resolved measurements and provide greater flexibility for data collection in experiments, including experiments that may not be explicitly time-resolved. I will give an overview of fast-framing detectors, as well as their present and future applications within the biological sciences.

 

 
"Radiation Damage to Protein Crystals by Intense Synchrotron Beams"

Robert E. Thorne1, Matthew A. Warkentin1, Jesse B. Hopkins1 and Donald Walko2
1Physics Department, Cornell University, Ithaca, NY 14853; 2Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439

Abstract: Advances in synchrotron sources, beamline optics, X-ray detectors, and sample handling will enable high-throughput serial crystallography on both frozen and room-temperature biomolecular crystals. How will radiation damage by the required high-flux-density beams limit the amount and quality of data that can obtained from each crystal and the throughput of these experiments?

We will review the experimental phenomenology of radiation damage to protein crystals, and discuss possible underlying mechanisms. At and near room temperature, experiments show that damage develops on a wide range of timescales extending up to ~ 1 s, orders of magnitude larger than that for free-radical diffusion and reaction, indicating that downstream structural rather than chemical relaxation processes are important in determining overall diffraction spot fading. This suggests the feasibility of outrunning radiation damage not just in femtoseconds as at free electron lasers, but in milliseconds at synchrotrons.

Initial experiments on the relatively radiation-hard proteins lysozyme and thaumatin at dose rates up to 680 kGy/s showed that crystal half doses at 260 K were increased by a factor of ~1.5-2 by collecting data in ~1 s [1]. More recent experiments have used dose rates up to 40 MGy/s, corresponding to photon fluxes of ~1016 photons/s/mm2. These dose rates lead to strong visible fluorescence, but the resulting damage is still tightly localized near the illuminated volume. At T=100 K, damage per unit dose appears to be approximately independent of dose rate for dose rates up to 40 MGy/s, corresponding to a minimum data collection time to the half-dose of ~0.5 s. At room temperature, damage per unit dose is reduced by a factor of 2-3 at 40 MGy/s, and data collection to the half-dose occurs in ~50 ms, consistent with our earlier work and more recent results of Owen et al. [2]. A relatively small increase in crystal half dose observed when dose rate and data collection times vary by more than a factor of 10 is consistent with an expected broad distribution of structural relaxation times [3]. However, some biomolecular crystals, such as those of the 70s ribosome, are nearly two orders of magnitude more radiation sensitive at room temperature than lysozyme and thaumatin [4], and for these crystals much larger fractional increases in half dose are expected. Large increases in data collected per crystal and decreases in crystals per structure enabled by ultra-intense synchrotron beams and fast framing detectors should enable an expansion of structural studies at and near room temperature.

[1] M. Warkentin, J. B. Hopkins, R. Badeau, A. M. Mulichak, L. J. Keefe & R. E. Thorne. J. Synch. Rad. 20, 7-13 (2013); M. Warkentin et al., Acta Cryst. D 68, 124-133 (2012).
[2] R. L. Owen, N. Paterson, D. Axford, J. Aishima, C. Schulze-Briese, J. Ren, E. E. Fry, D. I. Stuart, and G. Evans, Acta Cryst. D 70, 1248-1256 (2014); R. L. Owen et al., Acta Cryst. D 68, 810-818 (2012).
[3] M. Warkentin, R. Badeau, J. Hopkins & R. E. Thorne, Acta Cryst. D 67, 792-803 (2011).
[4] M. Warkentin, J. B. Hopkins, J. B. Haber, G. Blaha, and R. E. Thorne. Acta Cryst. D 70, 2890-2896 (2014).

 

 
"Watching biomolecules fold, interact and function"

Lois Pollack
School of Applied and Engineering Physics, Cornell University

Abstract: Small angle x-ray scattering (SAXS) reveals the structures of macromolecules in solution; time resolved SAXS adds information about the structural dynamics that impart biological activity. I will discuss numerous strategies for time resolved SAXS experiments, highlighting the flexibility of the technique. Examples will include discussions of biologically relevant structural dynamics triggered by changing solution conditions or light activation. I will also discuss recent work, combining contrast variation with time-resolved SAXS to monitor the changing structures of protein-nucleic acid complexes, such as the nucleosome core particle.

 

 
"Time-resolved SAXS: a way from structure to dynamics
of biomolecules"

Tsutomu Matsui
Stanford University / Stanford Synchrotron Radiation Lightsource (SSRL), Stanford Linear Accelerator Center (SLAC) National Laboratory

Abstract: Time-Resolved Small Angle X-ray Scattering (TR-SAXS) is an extremely powerful tool to investigate in-situ the conformational changes that biological systems are undergoing during the course of their biological function. The time regime of such changes is generally depending on the scale of the event. A TR-SAXS experiment using a stopped-flow mixer is an ideal tool to detect large scale transition like tertiary or quaternary structural changes of macromolecule, which typically occur in the millisecond time scale and above. However the use of stopped-flow mixers for TR-SAXS experiments on biological samples has often been difficult due to the large amount of material necessary.

Here I will update the latest status of our fast TR-SAXS setup using a customized stopped-flow mixer in order to reduce the sample consumption. This new setup allows us to obtain a TR-SAXS data set from as little as 30ul of sample volume at the present moment. It also eliminates the sample consuming priming of the tubing inside the stopped flow (no dead volume between shots) and thus substantially reduces the sample amount required for such experiments. Semi-automatic sample injection and wash cycle for the sample cell are employed at every single data collection. Recent scientific results using this setup are also being discussed.

 

 
"Picosecond Photobiology: Watching a Signaling Protein Function in Real Time via 150 Picosecond Time-Resolved X-ray Diffraction and Solution Scattering"

Philip A. Anfinrud
Laboratory of Chemical Physics, NIDDK, NIH, Bethesda, MD, USA

Abstract: To understand how signaling proteins function, it is crucial to know the time-ordered sequence of events that lead to the signaling state. We recently developed on the BioCARS beamline at the Advanced Photon Source the infrastructure required to characterize structural changes in proteins with 100-ps time resolution, and have used this capability to track the reversible photocycle of photoactive yellow protein following trans-to-cis photoisomerization of its p-coumaric acid (pCA) chromophore. Briefly, a picosecond laser pulse photoexcites pCA and triggers a structural change in the protein, which is probed with a suitably delayed picosecond X-ray pulse. When the protein is studied in a crystalline state, this “pump-probe” approach recovers time-resolved diffraction “snapshots” whose corresponding electron density maps can be stitched together into a real-time movie of the structural changes that ensue. However, the actual signaling state is not accessible in the crystalline state due to crystal packing constraints. This state is accessible in time-resolved small- and wide-angle X-ray scattering studies, which probe changes in the size, shape, and structure of the protein. The mechanistically detailed, near-atomic resolution description of the complete PYP photocycle developed from these studies provides a framework for understanding signal transduction in proteins, and for assessing and validating theoretical/computational approaches in protein biophysics. This research was supported in part by the Intramural Research Program of the NIH, NIDDK.

 

 
"Serial Millisecond Crystallography with an LCP injector"

Uwe Weierstall
Arizona State University, Tempe AZ 85008, USA

Abstract: Lipidic Cubic Phase (LCP) has been used successfully as a delivery medium for microcrystals at XFELs. To this end, an injection device has been designed that delivers a 50 micron stream of LCP with adjustable flow rate into the X-ray beam. The flow rate can be matched to the data acquisition rate of the experiment, so that no sample is wasted. Recent experiments have shown that the combination of new high speed detectors and high intensity microfocus beams at synchrotrons allow serial data acquisition from crystals in a flowing stream of LCP or other viscous media. The experiment design and recent results will be shown.